Method of reducing intermetallic compounds in matrix bit bondline by reduced temperature process

Abstract

A method for manufacturing a matrix drill bit includes: placing a metallic blank within a casting assembly including a mold having an inner surface formed into a negative shape of facial features of the drill bit; loading powder into an annulus formed between the blank and the mold, the powder including at least one of: ceramic powder and cermet powder; placing a binder alloy into the casting assembly over the blank and the mold; protecting the binder alloy from oxidation; inserting the casting assembly, blank, powder, and binder alloy into a furnace; operating the furnace to heat the protected binder alloy to an infiltration temperature between solidus and liquidus temperatures thereof, thereby infiltrating the powder with the binder alloy and forming a bit body; removing the bit body from the furnace; and after removal, attaching cutters to blades of the bit body.

1 . A method for manufacturing a matrix drill bit, comprising:
 placing a metallic blank within a casting assembly comprising a mold having an inner surface formed into a negative shape of facial features of the drill bit;   loading powder into an annulus formed between the blank and the mold, the powder comprising at least one of: ceramic powder and cermet powder;   placing a binder alloy into the casting assembly over the blank and the mold;   protecting the binder alloy from oxidation;   inserting the casting assembly, blank, powder, and binder alloy into a furnace;   operating the furnace to heat the protected binder alloy to an infiltration temperature between solidus and liquidus temperatures thereof, thereby infiltrating the powder with the binder alloy and forming a bit body;   removing the bit body from the furnace; and   after removal, attaching cutters to blades of the bit body.   
     
     
         2 . The method of  claim 1 , wherein the infiltration temperature is between 950° C. and 1061° C. 
     
     
         3 . The method of  claim 2 , wherein the infiltration temperature is between 1000° C. and 1050° C. 
     
     
         4 . The method of  claim 1 , wherein:
 the binder alloy is protected from oxidation by applying flux thereto, and   the furnace is operated in an uncontrolled atmosphere.   
     
     
         5 . The method of  claim 4 , wherein the flux has a working temperature range with a minimum working temperature less than the solidus temperature and a maximum working temperature greater than the liquidus temperature. 
     
     
         6 . The method of  claim 4 , wherein the flux includes, by weight: 25-92.5% boric acid, 2.5-25% potassium tetraborate, 2.5-25% dipotassium hexafluorosilicate, and 2.5-25% disodium tetraborate decahydrate. 
     
     
         7 . The method of  claim 4 , wherein:
 a weight of the flux applied equals to 0.1-10% times a weight of the powder, and   a weight of the binder alloy placed equals to 40-70% times a sum of the weight of the powder and the weight of the binder alloy.   
     
     
         8 . The method of  claim 1 , wherein the cutters are attached to the bit body by brazing. 
     
     
         9 . The method of  claim 1 , wherein the furnace is operated for an infiltration time between 15 minutes and 200 minutes. 
     
     
         10 . The method of  claim 1 , wherein:
 the powder is a body powder,   the method further comprises loading a shoulder powder into the annulus, and   the shoulder powder is a metal or alloy.   
     
     
         11 . The method of  claim 10 , wherein the shoulder powder is the metal component of the ceramic of the body powder. 
     
     
         12 . The method of  claim 1 , wherein the binder alloy is copper based. 
     
     
         13 . The method of  claim 12 , wherein the copper based alloy includes, by weight: 35-65% copper, 20-30% manganese, 10-20% nickel, and 5-15% zinc. 
     
     
         14 . The method of  claim 1 , wherein the blank is made from steel. 
     
     
         15 . A matrix drill bit manufactured according to the method of  claim 1 .